Tetrahedral Atom Ordering in a Zeolite Framework: A Key Factor Affecting Its Physicochemical Properties

Abstract

Table S2. Data Collection and Crystallographic Parameters for the Hydrated and Dehydrated Forms of K +-Exchanged Gallosilicate Natrolites with Different Degrees of T-atom Ordering material K-GaNAT-I(E) K-GaNAT-II(E) K-GaNAT-III(E) K-GaNAT-I(EC) K-GaNAT-II(EC) K-GaNAT-III(EC) unit cell composition

Structural characterization of various alkali cation forms of synthetic aluminosilicate natrolites

“…This strongly suggests that both j and q are almost independent of the T-atom ordering, but is highly dependent on the type of extraframework cations, which is consistent with the trend found in the Na þ form of natural aluminosilicate and synthetic gallosilicate natrolites [23,30]. Fig.…”

“…A similar result has also been observed for the dehydrated K þ form of the natural mineral natrolite, whereas a much longer time (7 days) was necessary to achieve rehydration when exposed to ambient conditions [34]. This behavior is substantially different from their gallosilicate analogs (i.e., K-TNU-3 and K-TNU-4), which show irreversible hydration after calcination [30]. When the Na þ back-exchange is performed on calcined K-PST-3 and K-PST-4, both materials attained almost complete Na þ backexchange, unlike the case of calcined K-TNU-3 and K-TNU-4 that show a strong dependency on T-atom ordering [30].…”

“…This behavior is substantially different from their gallosilicate analogs (i.e., K-TNU-3 and K-TNU-4), which show irreversible hydration after calcination [30]. When the Na þ back-exchange is performed on calcined K-PST-3 and K-PST-4, both materials attained almost complete Na þ backexchange, unlike the case of calcined K-TNU-3 and K-TNU-4 that show a strong dependency on T-atom ordering [30]. This result is unexpected because the introduction of larger and more electropositive Ga than Al into the zeolite framework can increase the ionicity of the TO 4 tetrahedra and hence the framework flexibility [36].…”

“…We have recently reported that the cation exchange properties of the as-made Na þ form of aluminosilicate natrolite zeolites depend strongly on the degree of T-atom ordering [18], like those of their gallosilicate analogs [30]: the Na þ ions in almost completely disordered PST-3 are fully exchanged with K þ and Rb þ ions, but are hardly exchanged with Cs þ . However, the almost completely ordered phase PST-4 shows a high but incomplete level of K þ exchange.…”

Towards Inorganic Porous Materials by Design: Looking for New Architectures

“…Very recently, it has been shown that the cation exchange ability of gallosilicate natrolites is strongly dependent on Si, Ga ordering, and that this is very likely related to a more fl exible framework in the more disordered natrolites. [ 36 ] In these cation exchange studies, but also in the one commented above on the selective adsorption properties of PST-1, [ 35 ] the crystallographic sizes of the windows are so small that any traffi c along the pores of the chemical species involved in the processes (either cations or small molecules) requires a large degree of framework deformation that can open the pores.…”